The present invention relates to a tapping fitting with a fitting housing made from plastic, particularly a flap or ball cock, for connection to a spigot of a plastic container for liquids, particularly an interior container of a transport and storage container, wherein the fitting housing is provided with a conductive device at least part of which is made from electrically conductive plastic for dissipating an electrostatic charge. The present invention further relates to a transport and storage container for liquids equipped with such a tapping fitting.
Liquid containers made from plastic are often used as transport and storage containers for liquids that may contain explosive components or are capable of forming explosive or readily ignitable gases in the liquid container. When such liquid containers are filled or emptied, friction between the liquid and the mantle of the liquid container may cause the buildup of electrostatic charges, which may result in ignition of the liquid or of the gases formed by the liquid.
In order to ensure that such ignition cannot happen, it has been suggested in the related art to dissipate the electrostatic charge via suitable means on the liquid container and/or the tapping fitting. To this end, EP 2 008 946 A1 describes an arrangement of a tapping fitting on a container for liquids that is provided with a drain port in such manner that an insertable port made from electrically conductive plastic material is provided between the drain spigot and the tapping fitting, wherein the insertable port is inserted with a cylindrical portion between an inner wall of the drain spigot and an outer wall of a filling port of the tapping fitting and protrudes radially beyond the tapping fitting with a flange rim, so that a welded connection may be created between the drain spigot of the liquid container and the insertable port and also between the insertable port and the tapping fitting when the tapping fitting is attached. An electrical conductor designed without to be independent of the insertable port is provided to form an electrically conductive connection between the insertable port and a ground potential.
The arrangement known from EP 2 008 946 A1 requires appropriate handling of the insertable port while the tapping fitting is mounted on the drain spigot of the liquid container. Moreover, a material-consistent and thus highly conductive bond is created between the tapping fitting and the insertable port but only in the areas where the welded join has actually been made. Furthermore, the separately constructed electrical conductor has to be connected to the insertable port in an additional mounting step.